cbcvebase.
CVE-2021-47038
published 2024-02-28

CVE-2021-47038: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: avoid deadlock between hci_dev->lock and socket lock Commit eab2404ba798…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.18%
7.5th percentile
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: avoid deadlock between hci_dev->lock and socket lock Commit eab2404ba798 ("Bluetooth: Add BT_PHY socket option") added a dependency between socket lock and hci_dev->lock that could lead to deadlock. It turns out that hci_conn_get_phy() is not in any way relying on hdev being immutable during the runtime of this function, neither does it even look at any of the members of hdev, and as such there is no need to hold that lock. This fixes the lockdep splat below: WARNING: possible circular locking dependency detected 5.12.0-rc1-00026-g73d464503354 #10 Not tainted bluetoothd/1118 is trying to acquire lock: ffff8f078383c078 (&hdev->lock){+.+.}-{3:3}, at: hci_conn_get_phy+0x1c/0x150 [bluetooth] but task is already holding lock: ffff8f07e831d920 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}, at: l2cap_sock_getsockopt+0x8b/0x610 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+.}-{0:0}: lock_sock_nested+0x72/0xa0 l2cap_sock_ready_cb+0x18/0x70 [bluetooth] l2cap_config_rsp+0x27a/0x520 [bluetooth] l2cap_sig_channel+0x658/0x1330 [bluetooth] l2cap_recv_frame+0x1ba/0x310 [bluetooth] hci_rx_work+0x1cc/0x640 [bluetooth] process_one_work+0x244/0x5f0 worker_thread+0x3c/0x380 kthread+0x13e/0x160 ret_from_fork+0x22/0x30 -> #2 (&chan->lock#2/1){+.+.}-{3:3}: __mutex_lock+0xa3/0xa10 l2cap_chan_connect+0x33a/0x940 [bluetooth] l2cap_sock_connect+0x141/0x2a0 [bluetooth] __sys_connect+0x9b/0xc0 __x64_sys_connect+0x16/0x20 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #1 (&conn->chan_lock){+.+.}-{3:3}: __mutex_lock+0xa3/0xa10 l2cap_chan_connect+0x322/0x940 [bluetooth] l2cap_sock_connect+0x141/0x2a0 [bluetooth] __sys_connect+0x9b/0xc0 __x64_sys_connect+0x16/0x20 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&hdev->lock){+.+.}-{3:3}: __lock_acquire+0x147a/0x1a50 lo

Affected

13 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.10.38-1 (bookworm)linux 5.10.38-1 (bookworm)
linuxlinux——
linuxlinux>= eab2404ba798a8efda2a970f44071c3406d94e57 < 7cc0ba67883c6c8d3bddb283f56c167fc837a5557cc0ba67883c6c8d3bddb283f56c167fc837a555
linuxlinux>= eab2404ba798a8efda2a970f44071c3406d94e57 < fee71f480bc1dec5f6ae3b0b185ff12a62bceabcfee71f480bc1dec5f6ae3b0b185ff12a62bceabc
linuxlinux>= eab2404ba798a8efda2a970f44071c3406d94e57 < 332e69eb3bd90370f2d9f2c2ca7974ff523dea17332e69eb3bd90370f2d9f2c2ca7974ff523dea17
linuxlinux>= eab2404ba798a8efda2a970f44071c3406d94e57 < 17486960d79b900c45e0bb8fbcac0262848582ba17486960d79b900c45e0bb8fbcac0262848582ba
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 5.11 < 5.11.215.11.21
linuxlinux_kernel>= 5.12 < 5.12.45.12.4
linuxlinux_kernel>= 5.7 < 5.10.375.10.37

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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